1. Field of the Invention
The present invention relates to a color filter using a surface plasmon, a liquid crystal display (LCD) device and a method for fabricating the same, and more particularly, to a color filter using a surface plasmon and having a three-dimensional (3D) pattern structure provided with a transmissive pattern for selectively transmitting light of a specific wavelength, an LCD device and a method for fabricating the same.
2. Discussion of the Related Art
As concerns about an information displays and demands for portable information media are increased, research and commercialization of flat panel displays (FPD) replacing the general display apparatus, Cathode Ray Tubes (CRT) are actively ongoing. One of these flat panel displays, a Liquid Crystal Display (LCD) device serves to display an image by using optical anisotropy of a liquid crystal (LC). Owing to an excellent resolution, color reproduction characteristic, and picture quality, the LCD device is being actively applied to a notebook, a desk top monitor, etc.
The LCD device is largely comprised of a color filter substrate, an array substrate, and an LC layer interposed between the color filter substrate and the array substrate.
The LCD device is fabricated through a plural number of mask processes (i.e., photo lithography process). Accordingly, required is a method for reducing the number of mask processes for enhanced productivity.
Hereinafter, a structure of the related art LCD device will be explained in more detail with reference to FIG. 1.
FIG. 1 is a disassembled perspective view schematically showing a structure of the related art LCD.
As shown in FIG. 1, the LCD device largely comprises a color filter substrate 5, an array substrate 10, and an LC layer 30 interposed between the color filter substrate 5 and the array substrate 10.
The color filter substrate 5 consists of a color filter (C) composed of a plurality of sub color filters 7 for implementing red, green and blue (RGB) colors, a black matrix 6 for dividing the sub color filters 7 from each other and shielding light passing through the LC layer 30, and a transparent common electrode 8 for applying a voltage to the LC layer 30.
The array substrate 10 consists of a plurality of gate lines 16 and data lines 17 arranged in horizontal and vertical directions to define a plurality of pixel regions (P), Thin Film Transistors (TFT), switching devices formed at intersections between the gate lines 16 and the data lines 17, and pixel electrodes 18 formed in the pixel regions (P).
The color filter substrate 5 and the array substrate 10 facing each other are bonded to each other by a sealant (not shown) formed on an outer periphery of an image display region, thereby constituting an LC panel. The color filter substrate 5 and the array substrate 10 are bonded to each other by alignment keys (not shown) formed at the color filter substrate 5 or the array substrate 10.
In order to prevent light leakage due to an alignment error when bonding the two substrates to each other, a line width of the black matrix is set to be wide, thereby obtaining an alignment margin. This may reduce an aperture ratio of the LC panel.
The general color filter used in the LCD device implements colors by absorbing light of unnecessary colors for disappearance with using pigments or dyes, and by selectively transmitting light of desired colors. This may allow only one of RGB colors, from white incident light, to be transmitted to one sub-pixel. Accordingly, it is difficult to have a transmittance rate more than 30%. Due to this low transmittance rate of the LC panel, power consumption by a backlight is increased.
FIG. 2 is an exemplary view schematically showing a transmittance rate of the LC panel when applying a color filter using a general pigment dispersing method.
Referring to FIG. 2, as light incident from a backlight has a decreased optical amount decreased while sequentially passing through a polarizer, a TFT array, an LC and a color filter, a transmittance rate is reduced to 5% or less than.
Here, the polarizer, the TFT array and the color filter approximately have transmittance rates of ˜40%, 45˜55% and ˜25%, respectively.
The general color filter is fabricated with complicated processes since it repeatedly undergoes color resist coating, exposure to light, development and hardening processes according to each color.
Furthermore, in order to fabricate the color filter on the color filter substrate, color filter processing lines have to be implemented separately from TFT processing lines. This may increase line installation costs.